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Toru Sato

Publications and source records attributed to Toru Sato.

At least 19 recordsLinked to original sources
PubMed2007

Sociotropy-autonomy and interpersonal problems.

Sociotropy and autonomy are conceptualized as two personality dimensions that relate to an individual's vulnerability to depression. Sociotropy is characterized as an excessive investment in interpersonal relationships, and autonomy is characterized as an excessive concern with personal achievement and control. This study examined the relationships between sociotropy and autonomy, and a variety of interpersonal problems with close and nonclose others. Results suggested that sociotropic individuals are overly nurturant to nonclose others but vindictive to individuals who are close to them. In contrast, autonomous individuals were found to be domineering to nonclose others but socially avoidant toward people close to them. These findings are discussed in the context of recent research regarding the interpersonal patterns associated with sociotropy and autonomy.

Adolescent↗
PubMed2006

Signal peptide peptidase: biochemical properties and modulation by nonsteroidal antiinflammatory drugs.

Signal peptide peptidase (SPP) is an intramembrane aspartyl protease that cleaves remnant signal peptides after their release by signal peptidase. SPP contains active site motifs also found in presenilin, the catalytic component of the gamma-secretase complex of Alzheimer's disease. However, SPP has a membrane topology opposite that of presenilin, cleaves transmembrane substrates of opposite directionality, and does not require complexation with other proteins. Here we show that, upon isolation of membranes and solubilization with detergent, the biochemical characteristics of SPP are remarkably similar to gamma-secretase. The majority of the SPP-catalyzed cleavages occurred at a single site in a synthetic substrate based on the prolactin (Prl) signal sequence. However, as seen with cleavage of substrates by gamma-secretase, additional cuts at other minor sites are also observed. Like gamma-secretase, SPP is inhibited by helical peptidomimetics and apparently contains a substrate-binding site that is distinct from the active site. Surprisingly, certain nonsteroidal antiinflammatory drugs known to shift the site of proteolysis by gamma-secretase also alter the cleavage site of Prl by SPP. Together, these findings suggest that SPP and presenilin share certain biochemical properties, including a conserved drug-binding site for allosteric modulation of substrate proteolysis.

Amino Acid Sequence↗
PubMed2006

Mammalian Polycomb complexes are required for Peyer's patch development by regulating lymphoid cell proliferation.

The vertebrate Polycomb Group (PcG) genes encode proteins that form large multimeric and chromatin-associated complexes implicated in the stable repression of developmentally essential genes. Rnf110 and Phc2 are shown to be components of mammalian PcG multimeric complexes in HeLa cells. Here we report defects in Peyer's patch (PP) development in Rnf110 mutant mice, which is synergically exaggerated by Phc2 mutation. PP development involves a series of inductive interactions and subsequent differentiation and proliferation between lymphoid and mesenchymal cells in late gestational stage. Rnf110 and Phc2 mutations impair development of PP anlagen by affecting proliferation of lymphoid lineage cells populated in PP anlagen in gene-dosage dependent manner. We suggest that PcG complexes may act to mediate certain inductive signals maybe through IL-7Ralpha to allow sufficient proliferation of lymphoid inducer cells during PP organogenesis.

Animals↗
PubMed2006

Diagnosis of deep vein thrombosis after operation for fracture of the proximal femur: comparative study of ultrasonography and venography.

BACKGROUND: We compared investigative methods to study the diagnostic capability of ultrasonography. Subjects were 75 patients with proximal femur fractures who underwent surgery from March 2002 to December 2003. METHODS: Biochemical assays were carried out on days 3 and 7, and D-dimer levels were investigated as a time series. Ascending lower limb venography and ultrasonography were carried out nearly simultaneously in all cases on day 7. RESULTS: The incidence of deep vein thrombosis (DVT)-positive findings on venography was 61.3% (46/75). Venography results demonstrated a diagnostic sensitivity of 95.5% and specificity of 91.4% using a D-dimer cutoff of 1microg/ml on postoperative day 7. By ultrasonography, diagnostic sensitivity for DVT was 78.3%, and specificity was 96.5%. Among all proximal area cases, there were 18 limbs with DVT seen on venography among which were 17 limbs in cases demonstrating DVT at the same site on ultrasonography, a correct diagnosis rate of 94.4%. CONCLUSIONS: For the diagnosis of a thrombus more proximal than the popliteal area, a location at high risk for occurrence of pulmonary embolism, ultrasonography provided results nearly on par with those obtained by venography. Thus, we believe that ultrasonography allowed a more noninvasive, accurate diagnosis and more rapid treatment in cases where D-dimer values were 1 microg/ml or more on postoperative day 7.

Adult↗
PubMed2006

[CT findings of pulmonary hypertension].

For the treatment for pulmonary hypertension (PH), the differential diagnosis of its causal diseases is essential. To determine whether X-ray CT is useful for differentiating PH, we reviewed CT findings of 53 patients (18 men and 35 women, mean age of 44.9) given a diagnosis of PH, consisting of 25 with primary pulmonary hypertension (PPH), 18 with chronic pulmonary embolism (cPE), 6 with Eisenmenger syndrome, 5 cases of collagen diseases, 2 of acute PE, and 1 of cor pulmonale. The intrapulmonary distribution of CT findings (ground glass opacity [GGO], mosaic attenuation, striation and/or infiltration, and interlobular septal thickening) were reviewed and scored on a 4-point scale (grade 0: no findings, 1: involving one third of the lung, 2: involving one-two thirds, and 3: diffuse distribution) by two radiologists who reached a consensus. PPH showed preferentially diffuse distribution of GGO as compared with cPE (p<0.05). However, there was no apparent relationship between the pulmonary vascular resistance and the distribution of GGO in PPH cases. The mosaic attenuation pattern was more frequent in cPE (43%) than PPH (12% ; p<0.05). Striation and/or infiltration was observed in 36% of cPE, but only 4% of PPH. Interlobular septal thickening was seen in 16% of PPH, and 0% in cPE. Evaluation of CT findings is useful to differentiate PH.

Adolescent↗
PubMed2005

Acute toxicity of temporally varying seawater CO2 conditions on juveniles of Japanese sillago (Sillago japonica).

CO(2) ocean storage by which liquefied CO(2) is injected into the deep-sea to mitigate the climate change would increase the CO(2) concentrations of the surrounding seawater. The biological impacts of such dynamic CO(2) environments are, however, unknown. We examined the acute toxicity of temporally changing seawater CO(2) concentrations on juveniles of Sillago japonica. Step-wise increases in ambient CO(2) to fCO(2) (fractional CO(2) concentration of the gas mixture bubbled into seawater) levels of 7% and 9% resulted in mortalities of 0.15 and 0.40-0.67 after 18 h, respectively. In contrast, one-step increases to these CO(2) levels killed all fish within 15 min. Further, a sudden drop of fCO(2) from 9-10% CO(2) to normocapnia (0.038%) killed all the surviving fish within a few minutes. These results demonstrate that impacts of ocean CO(2) storage need to be examined under conditions mimicking the dynamic changes in CO(2) levels expected to occur by the CO(2) injection procedure.

Animals↗
PubMed2005

Blocking the cleavage at midportion between gamma- and epsilon-sites remarkably suppresses the generation of amyloid beta-protein.

To examine how gamma- and epsilon-cleavages of beta-amyloid precursor protein (APP) are related, each cleavage site was replaced with a stretch of Trp that cannot be cleaved by gamma-secretase. Replacement of the gamma- or epsilon-site significantly suppressed secretion of amyloid beta-protein (Abeta), and produced longer Abeta or longer APP intracellular domain, respectively. This cleavage at the midportion between gamma- and epsilon-sites was also gamma-secretase-dependent. Blocking this cleavage with a Trp stretch remarkably suppressed Abeta generation, indicating that the midportion cleavage is required for the generation of Abeta.

Amino Acid Sequence↗
PubMed2005

Random mutagenesis of presenilin-1 identifies novel mutants exclusively generating long amyloid beta-peptides.

Familial Alzheimer disease-causing mutations in the presenilins increase production of longer pathogenic amyloid beta-peptides (A beta(42/43)) by altering gamma-secretase activity. The mechanism underlying this effect remains unknown, although it has been proposed that heteromeric macromolecular complexes containing presenilins mediate gamma-secretase cleavage of the amyloid beta-precursor protein. Using a random mutagenesis screen of presenilin-1 (PS1) for PS1 endoproteolysis-impairing mutations, we identified five unique mutants, including R278I-PS1 and L435H-PS1, that exclusively generated a high level of A beta43, but did not support physiological PS1 endoproteolysis or A beta40 generation. These mutants did not measurably alter the molecular size or subcellular localization of PS1 complexes. Pharmacological studies indicated that the up-regulation of activity for A beta43 generation by these mutations was not further enhanced by the difluoroketone inhibitor DFK167 and was refractory to inhibition by sulindac sulfide. These results suggest that PS1 mutations can lead to a wide spectrum of changes in the activity and specificity of gamma-secretase and that the effects of PS1 mutations and gamma-secretase inhibitors on the specificity are mediated through a common mechanism.

Allosteric Site↗
PubMed2005

Extended probit mortality model for zooplankton against transient change of PCO(2).

The direct injection of CO(2) in the deep ocean is a promising way to mitigate global warming. One of the uncertainties in this method, however, is its impact on marine organisms in the near field. Since the concentration of CO(2), which organisms experience in the ocean, changes with time, it is required to develop a biological impact model for the organisms against the unsteady change of CO(2) concentration. In general, the LC(50) concept is widely applied for testing a toxic agent for the acute mortality. Here, we regard the probit-transformed mortality as a linear function not only of the concentration of CO(2) but also of exposure time. A simple mathematical transform of the function gives a damage-accumulation mortality model for zooplankton. In this article, this model was validated by the mortality test of Metamphiascopsis hirsutus against the transient change of CO(2) concentration.

Animals↗
PubMed2005

Characterization of the peri-implant epithelium in hamster palatine mucosa: behavior of Merkel cells and nerve endings.

The purpose of this study was to investigate the relationship between Merkel cells and nerve elements during tissue regeneration after receiving dental implants. Golden hamsters were divided into 3 groups and titanium alloy implants were fixed in their left-side maxilla through the third palatine rug. Animals were sacrificed at 1, 2, 3, 4, 5, 6, and 7 days after the implantation and tissues were characterized at the immunohistochemical and morphological levels. CK 20 and PGP 9.5 antibodies which react with Merkel cells and nerve fibers were used. Immunohistochemically, no CK 20-positive Merkel cells were seen in the peri-implant epithelium throughout the 7 days. However, starting at day 4, PGP 9.5-positive nerve fibers appeared in the connective tissue, and by day 7, nerve fibers had invaded the more superficial layer of the peri-implant epithelium compared to the mucosa removal control group. At the electron microscopic level, the intercellular spaces of the regenerating epithelium in the mucosa removal control group were small. In contrast, intercellular spaces of the peri-implant epithelium tended to be wide and regenerating nerve fibers invaded those intercellular spaces. In both the mucosa removal control group and the implantation group, the basal lamina and connective tissues regenerated completely. However, clear Merkel cells containing neurosecretory granules were not observed. Taken together, our results indicate that Merkel cells in the hamster palatine mucosa do not regenerate in the peri-implant epithelium. However, regenerative nerve fibers seem to play essential roles as part of the defense and sensory systems around the peri-implant epithelium to compensate for the weakened defense mechanism.

Animals↗
PubMed2005

The Eysenck Personality Questionnaire Brief Version: factor structure and reliability.

The short scale of the Eysenck Personality Questionnaire-Revised (EPQR-S; H. J. Eysenck & S. B. G. Eysenck, 1992) is a 48-item personality questionnaire primarily designed to measure an individual's level of extraversion (vs. introversion) and neuroticism. Although L. J. Francis, L. B. Brown, and R. Philipchalk (1992) created the Eysenck Personality Questionnaire Revised-Abbreviated (EPQR-A), an even briefer version of the EPQR-S, the reliability coefficients of some of the measures have been less than satisfactory (S. Forrest, C. A. Lewis, & M. Shevlin, 2000). Because brevity and reliability are both extremely important, the author of the present study created a briefer version of the EPQR-S, more reliable than the EPQR-A, by making slight alterations in the item content as well as the response format of the EPQR-S. Two hundred and sixty eight participants completed the original EPQR-S and the 24-item newly revised briefer version of the EPQR-S (EPQ-BV) twice. The findings revealed that the EPQ-BV has good internal consistency, test-retest reliability, and concurrent validity. A principal component analysis revealed a solution with factor loadings that accurately reflected the primary measures of the EPQR-S. These findings are discussed in relation to the psychometric properties of the EPQR-A and the original version of the EPQR-S.

Adult↗
PubMed2004

Sociotropy-autonomy and situation-specific anxiety.

Sociotropy and autonomy are conceptualized as two personality dimensions that relate to individuals' vulnerability to anxiety and depression. Sociotropy is characterized as an excessive investment in interpersonal relationships, and autonomy is characterized as an excessive concern with independence as well as a lack of concern for others. The present study investigated the relationships between sociotropy-autonomy and trait anxiety associated with four types of situations, i.e., Social Evaluation, Physical Danger, Ambiguous Situation, and Daily Routine. 255 undergraduate students completed the Sociotropy-Autonomy Scale, the Endler Multidimensional Anxiety Scale, and the Beck Depression Inventory. Analyses indicated that scores on Sociotropy were positively correlated with rated trait anxiety in situations of Social Evaluation, Physical Danger, and Ambiguous Situations, whereas scores on Autonomy were positively correlated with rated trait anxiety in Daily Routines. These findings are discussed in the context of the diathesis-stress model of anxiety and depression.

Adolescent↗
PubMed2004

Assessment of smoking status among workers using an improved colorimetric method.

To monitor smoking status among workers, we improved the colorimetric method to detect cotinine and other nicotine metabolites in urine. In adding ethanol in the reaction mixture, the quantitative measurable time defined as the duration with more than 95% of the peak absorbance, extended to 80 min in contrast to 16 min in the original method. As the analytical condition, a aliquot of urine sample (0.5 ml) was mixed with 0.5 ml of ethanol, with 0.2 ml of 4 M acetate buffer (pH: 4.7), with 0.1 ml of 150 mM KCN, with 0.1 ml of 0.44 M chloramin and then with 0.5 ml of 78 mM barbituric acid. A linear relationship was observed between cotinine concentration up to 80 microM and absorbance at 508 nm (r=0.998, p<0.01). Mean levels of nicotine metabolites among non smokers and smokers were 4.9 and 47.4 microM cotinine equivalent, respectively. Sensitivity and specificity were 96.1% and 96.7%, respectively for nicotine metabolites concentration among workers (n=385) when adopting 6.9 microM cotinine equivalent as a cut off value and the area under the ROC curve was 0.982. This method can be applicable to quantitative detection of smoking status.

Colorimetry↗
PubMed2003

Potential link between amyloid beta-protein 42 and C-terminal fragment gamma 49-99 of beta-amyloid precursor protein.

A novel cleavage of beta-amyloid precursor protein (APP), referred to as epsilon-cleavage, occurs downstream of the gamma-cleavage and generates predominantly a C-terminal fragment (CTFgamma) that begins at Val-50, according to amyloid beta-protein (Abeta) numbering. Whether this cleavage occurs independently of, or is coordinated with, gamma-cleavage is unknown. Using a cell-free system, we show here that, although Abeta40 and CTFgamma 50-99 were the predominant species produced by membranes prepared from cells overexpressing wild-type (wt) APP and wt presenilin (PS) 1 or 2, the production of CTFgamma 49-99, which begins at Leu-49, was remarkably enhanced in membranes from cells overexpressing mutant (mt) APP or mtPS1/2 that increases the production of Abeta42. Furthermore, a gamma-secretase inhibitor, which suppresses Abeta40 production and paradoxically enhances Abeta42 production at low concentrations, caused the proportion of CTFgamma 50-99 to decrease and that of CTFgamma 49-99 to increase significantly. These results strongly suggest a link between the production of Abeta42 and CTFgamma 49-99 and provide an important insight into the mechanisms of altered gamma-cleavage caused by mtAPP and mtPS1/2.

Amyloid beta-Peptides↗
PubMed2003

Mesenchymal expression of Foxl1, a winged helix transcriptional factor, regulates generation and maintenance of gut-associated lymphoid organs.

The Foxl1 gene, which encodes a winged helix transcriptional regulator, is expressed in the mesenchymal layer of developing and mature gastrointestinal tract. Foxl1-deficient mice exhibit various defects not only in the epithelial layer of the gastrointestinal tract but also in gut-associated lymphoid tissues. In the small intestine of Foxl1-deficient mice, the formation of Peyer's patches is affected, particularly in the caudal region. This alteration is shown to be due to the delayed formation of Peyer's patches organizing centers as revealed by the expressions of VCAM1 and IL-7 receptor alpha-chain at 17.5 days postcoitus. Peyer's patch defects are concordant with the significantly decreased expression of Lymphotoxin beta-receptor in the caudal region of fetal intestine. Foxl1 is suggested to regulate the responsiveness of fetal intestinal mesenchymal cells to inductive signals mediated by Lymphotoxins during Peyer's patch organogenesis. In addition, constitutive outgrowth of colonic patches due to defects in radioresistant stromal components of colonic patches are seen in Foxl1-deficient mice. Because of the functional similarities of hypertrophic colonic patches to those seen in hapten-induced experimental colitis, this hypertrophy is suggested to involve Lymphotoxin beta-receptor signaling. Together, the data suggest that Foxl1 might be involved in cellular responses of gut-associated lymphoid tissues dependent upon the Lymphotoxins/Lymphotoxin beta-receptor axis.

Animals↗
PubMed2003

Distinct mechanisms by mutant presenilin 1 and 2 leading to increased intracellular levels of amyloid beta-protein 42 in Chinese hamster ovary cells.

To characterize the properties of presenilin (PS) 1- and PS2-associated gamma-secretases, we established stable transfectants overexpressing amyloid precursor protein and wild-type (wt) or a number of mutant (mt) PS1 or PS2. Quantification of the intracellular amyloid beta-protein (Abeta) levels in mtPS1 and mtPS2 cell lines revealed the presence of two subtypes. One group consists of N141I, M239V, and T122P mutations of the PS2 gene and homologous mutations of PS1, N135D and M233T. These mutations led to an increase in the intracellular Abeta42 levels and a concomitant decrease in the intracellular Abeta40 levels. A cell-free assay for Abeta production using the membranes prepared from these transfectants exhibited predominant cleavage at position Abeta42 with marginal production of Abeta40. The other group consists of M146L, H163R, and G384A mutations of PS1, leading only to an increase in the intracellular Abeta42 levels. While the intracellular Abeta levels in M146L cells were consistent with the results from cell-free Abeta production, H163R and G384A cells showed significant discrepancies between the intracellular Abeta levels and cell-free Abeta production. Thus, all the mtPS1/2 examined here result in increases in the intracellular Abeta42 levels. This suggests that the underlying mechanisms for this shared phenotype may be diverse.

Amino Acid Substitution↗
PubMed2003

Sociotropy and autonomy: the nature of vulnerability.

Sociotropy and autonomy are 2 personality dimensions related to an individual's vulnerability to depression (A. T. Beck, 1983). The Sociotropy-Autonomy Scale (D. A. Clark, R. A. Steer, A. T. Beck, & L. Ross, 1995) and the Personal Style Inventory (C. J. Robins et al., 1994) were developed to assess these personality dimensions independent of each other. The present study is an examination of the relationship between the 2 scales and an attempt to specify the various factors that emerge when the items of the 2 scales are integrated. Participants (N = 514) responded to the Personal Style Inventory, the Sociotropy-Autonomy Scale, and the Beck Depression Inventory (A. T. Beck & R. A. Steer, 1987). A principal component analysis on all of the items of the 2 scales revealed a four-factor structure (2 sociotropy and 2 autonomy). The author examined the relationships between depression, the 4 factors, and the 2 original scales and discussed the results in the context of vulnerability to depression.

Adolescent↗